Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19693
Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Madison River, Yellowstone National Park, Wyoming
Image ID: 19697
Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19698
Elk, bull elk, adult male elk with large set of antlers. By September, this bull elk's antlers have reached their full size and the velvet has fallen off. This bull elk has sparred with other bulls for access to herds of females in estrous and ready to mate.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19721
Roosevelt elk, adult bull male with large antlers. This bull elk has recently shed the velvet that covers its antlers. While an antler is growing, it is covered with highly vascular skin called velvet, which supplies oxygen and nutrients to the growing bone; once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler, which is itself shed after each mating season. Roosevelt elk grow to 10' and 1300 lb, eating grasses, sedges and various berries, inhabiting the coastal rainforests of the Pacific Northwest.
Species: Roosevelt elk, Cervus canadensis roosevelti
Location: Redwood National Park, California
Image ID: 25890
Roosevelt elk, adult bull male with large antlers. This bull elk has recently shed the velvet that covers its antlers. While an antler is growing, it is covered with highly vascular skin called velvet, which supplies oxygen and nutrients to the growing bone; once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler, which is itself shed after each mating season. Roosevelt elk grow to 10' and 1300 lb, eating grasses, sedges and various berries, inhabiting the coastal rainforests of the Pacific Northwest.
Species: Roosevelt elk, Cervus canadensis roosevelti
Location: Redwood National Park, California
Image ID: 25878
Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Madison River, Yellowstone National Park, Wyoming
Image ID: 19700
Bull elk in sage brush with large rack of antlers during the fall rut (mating season). This bull elk has sparred with other bulls to establish his harem of females with which he hopes to mate.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19718
Sea otters mating. The male holds the female's head or nose with his jaws during copulation. Visible scars are often present on females from this behavior. Sea otters have a polygynous mating system. Many males actively defend territories and will mate with females that inhabit their territory or seek out females in estrus if no territory is established. Males and females typically bond for the duration of estrus, or about 3 days.
Species: Sea otter, Enhydra lutris
Location: Elkhorn Slough National Estuarine Research Reserve, Moss Landing, California
Image ID: 21606
Bull elk, antlers bearing velvet, Gibbon Meadow. Elk are the most abundant large mammal found in Yellowstone National Park. More than 30,000 elk from 8 different herds summer in Yellowstone and approximately 15,000 to 22,000 winter in the park. Bulls grow antlers annually from the time they are nearly one year old. When mature, a bulls rack may have 6 to 8 points or tines on each side and weigh more than 30 pounds. The antlers are shed in March or April and begin regrowing in May, when the bony growth is nourished by blood vessels and covered by furry-looking velvet.
Species: Elk, Cervus canadensis
Location: Gibbon Meadows, Yellowstone National Park, Wyoming
Image ID: 13154
Bull elk in sage brush with large rack of antlers during the fall rut (mating season). This bull elk has sparred with other bulls to establish his harem of females with which he hopes to mate.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19702
A sea otter eats a clam that it has taken from the shallow sandy bottom of Elkhorn Slough. Because sea otters have such a high metabolic rate, they eat up to 30% of their body weight each day in the form of clams, mussels, urchins, crabs and abalone. Sea otters are the only known tool-using marine mammal, using a stone or old shell to open the shells of their prey as they float on their backs.
Species: Sea otter, Enhydra lutris
Location: Elkhorn Slough National Estuarine Research Reserve, Moss Landing, California
Image ID: 21612
Large male elk (bull) in snow covered meadow near Madison River. Only male elk have antlers, which start growing in the spring and are shed each winter. The largest antlers may be 4 feet long and weigh up to 40 pounds. Antlers are made of bone which can grow up to one inch per day. While growing, the antlers are covered with and protected by a soft layer of highly vascularised skin known as velvet. The velvet is shed in the summer when the antlers have fully developed. Bull elk may have six or more tines on each antler, however the number of tines has little to do with the age or maturity of a particular animal.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19692
Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19695
Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19703
Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19708